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Public Notice of Mosquito Control Activities

The Cowlitz County Mosquito Control District will begin seasonal activities soon. Only when mosquito larva is found will the district use one of the following larvicides.

  1. VectoBac G (Bacillus Thuringiensis, subspecies Israelensis): specific for mosquito larva
  2. Vectolex-CG (Bacillus Sphaericus): specific for mosquito larva
  3. Vectomax (Bacillus Thuringiensis, subspecies Israelensis and Bacillus sphaericus): specific for mosquito larva
  4. Natular (Spinosad) the first mosquito larvicide evaluated as a Reduced Risk Product by the EPA
  5. Altosid (S-Methoprene) a growth inhibitor active on mosquito larva
  6. Agnique (poly-alpha –w-hydroxy): a monomolecular surface film used for late stage larva and pupa
  7. COCOBEAR Oil (white mineral oil): for late stage larva and pupa on impounded water bodies

Later in the season and only in areas where adult mosquitoes cause extreme annoyance or mosquito transmitted disease is present will the district adulticide using:

  • Permanone (permethrin) which is Ultra Low Volume fogged at a rate between 0.024 and 0.112 ounces per acre.

Mosquito control activities will continue throughout the season until mid-October.

For further information or to report mosquito problems, visit our website at or phone the Mosquito Control Hot Line (360) 425-5658. Additional information and schedule changes will be posted on our website.

You may also contact the Ecology Aquatic Pesticides Permit Manager, Jon Jennings at: (360) 407-6283